Estimation of damping characteristics and optimization of curvilinear fiber shapes for composites fabricated by electrodeposition resin molding

The effect of both curvilinear fiber orientation and thickness distribution on modal damping of carbon fiber reinforced plastics (CFRP) fabricated by electrodeposition resin molding (ERM) was investigated. Tailored fiber placement (TFP) was used to manufacture carbon fiber (CF) performs with continuous curvilinear fiber paths or variable-axial properties. The damping of composites was calculated using the concept of specific damping capacity (SDC). Fiber shapes was optimized to maximize the first modal SDC using particle swarm optimization (PSO). As a result, the optimum fiber shape improves both the first natural frequency and modal SDC in comparison with several unidirectional fiber shapes

In Vitro Spermatogenesis in Explanted Adult Mouse Testis Tissues.

Research on in vitro spermatogenesis is important for elucidating the spermatogenic mechanism. We previously developed an organ culture method which can support spermatogenesis from spermatogonial stem cells up to sperm formation using immature mouse testis tissues. In this study, we examined whether it is also applicable to mature testis tissues of adult mice. We used two lines of transgenic mice, Acrosin-GFP and Gsg2-GFP, which carry the marker GFP gene specific for meiotic and haploid cells, respectively. Testis tissue fragments of adult GFP mice, aged from 4 to 29 weeks old, which express GFP at full extension, were cultured in medium supplemented with 10% KSR or AlbuMAX. GFP expression decreased rapidly and became the lowest at 7 to 14 days of culture, but then slightly increased during the following culture period. This increase reflected de novo spermatogenesis, confirmed by BrdU labeling in spermatocytes and spermatids. We also used vitamin A-deficient mice, whose testes contain only spermatogonia. The testes of those mice at 13-21 weeks old, showing no GFP expression at explantation, gained GFP expression during culturing, and spermatogenesis was confirmed histologically. In addition, the adult testis tissues of Sl/Sld mutant mice, which lack spermatogenesis due to Kit ligand mutation, were cultured with recombinant Kit ligand to induce spermatogenesis up to haploid formation. Although the efficiency of spermatogenesis was lower than that of pup, present results showed that the organ culture method is effective for the culturing of mature adult mouse testis tissue, demonstrated by the induction of spermatogenesis from spermatogonia to haploid cells

Stereomicroscopic view of cultured adult mouse testis tissues.

<p>(A) Six-week-old <i>Acr</i>-GFP mouse testis tissue fragments on culture days 0, 3, and 10. Upper row is GFP excitation view and lower row is bright view. (B) Six-week-old <i>Acr</i>-GFP mouse testis tissue fragments on culture days 0, 15, and 82. Weak GFP expression was maintained. (C-E) Immunohistochemistry of cultured tissues with antibodies to BrdU and GFP, counterstained with Hoechst. Testis tissue fragments of 6-week-old <i>Acr</i>-GFP (C and D) and 24-week-old <i>Gsg2</i>-GFP (E) mice were cultured, and then analyzed on days 42 (<b>C</b>), 85 (<b>D</b>), and 48 (<b>E</b>), respectively. The dashed rectangular area in the left picture of C is enlarged on the right. Arrows indicate BrdU-positive round spermatids in C and elongating spermatids in E. Scale bars, 1 mm (A, B); 10 μm (C, E); 50 μm (D).</p

Summary of adult <i>Sl/Sl</i>^<i>d</i> mouse experiment, chronologically arranged.

<p>Summary of adult <i>Sl/Sl</i>^<i>d</i> mouse experiment, chronologically arranged.</p

Summary of adult <i>Sl/Sl</i>^<i>d</i> mouse experiment.

<p>Summary of adult <i>Sl/Sl</i>^<i>d</i> mouse experiment.</p